A researcher is investigating the effect of background noise on classroom performance for children aged 10 to 12. One class of N = 15 students who listens to calming music each day while working on arithmetic problems is chosen as the experimental group. Another class of N = 16 students serves as a control group with no music. Accuracy scores are measured for each child, and the average for students in the music condition is X = 86.4 with SS = 1550. For the no-music condition, the average is X = 78.8 with SS = 1235..